CVE-2026-35568: CWE-346: Origin Validation Error in modelcontextprotocol java-sdk
CVE-2026-35568 is a high-severity vulnerability in the Model Context Protocol (MCP) Java SDK versions prior to 1.0.0. It is a DNS rebinding vulnerability that allows an attacker to access a locally or network-private MCP server through a victim's browser that is local or network adjacent. This enables the attacker to perform any tool call to the MCP server as if they were a locally running MCP-connected AI agent. The vulnerability is fixed in version 1.0.0 of the java-sdk.
AI Analysis
Technical Summary
The MCP Java SDK prior to version 1.0.0 contains a DNS rebinding vulnerability classified under CWE-346 (Origin Validation Error). This flaw allows an attacker to bypass origin checks by manipulating DNS responses, enabling access to MCP servers that are local or within the victim's network. Exploitation requires the victim to access a malicious webpage, which then interacts with the MCP server via the victim's browser. The attacker can issue commands to the MCP server with the same privileges as a local MCP-connected AI agent. The vulnerability has a CVSS 4.0 base score of 7.6, indicating high severity. The issue is resolved in MCP Java SDK version 1.0.0.
Potential Impact
Successful exploitation allows an attacker to perform arbitrary tool calls on a local or network-private MCP server via the victim's browser, effectively impersonating a locally connected MCP AI agent. This could lead to unauthorized actions within the MCP environment, potentially compromising system integrity or confidentiality. There are no known exploits in the wild at this time.
Mitigation Recommendations
This vulnerability is fixed in MCP Java SDK version 1.0.0. Users should upgrade to version 1.0.0 or later to remediate this issue. No other official remediation level or temporary fix is provided. Patch status is confirmed by the vendor advisory stating the fix is included in version 1.0.0.
CVE-2026-35568: CWE-346: Origin Validation Error in modelcontextprotocol java-sdk
Description
CVE-2026-35568 is a high-severity vulnerability in the Model Context Protocol (MCP) Java SDK versions prior to 1.0.0. It is a DNS rebinding vulnerability that allows an attacker to access a locally or network-private MCP server through a victim's browser that is local or network adjacent. This enables the attacker to perform any tool call to the MCP server as if they were a locally running MCP-connected AI agent. The vulnerability is fixed in version 1.0.0 of the java-sdk.
CVSS v4.0
Score 7.6high
Affected software
pkg:maven/modelcontextprotocol/java-sdkRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The MCP Java SDK prior to version 1.0.0 contains a DNS rebinding vulnerability classified under CWE-346 (Origin Validation Error). This flaw allows an attacker to bypass origin checks by manipulating DNS responses, enabling access to MCP servers that are local or within the victim's network. Exploitation requires the victim to access a malicious webpage, which then interacts with the MCP server via the victim's browser. The attacker can issue commands to the MCP server with the same privileges as a local MCP-connected AI agent. The vulnerability has a CVSS 4.0 base score of 7.6, indicating high severity. The issue is resolved in MCP Java SDK version 1.0.0.
Potential Impact
Successful exploitation allows an attacker to perform arbitrary tool calls on a local or network-private MCP server via the victim's browser, effectively impersonating a locally connected MCP AI agent. This could lead to unauthorized actions within the MCP environment, potentially compromising system integrity or confidentiality. There are no known exploits in the wild at this time.
Mitigation Recommendations
This vulnerability is fixed in MCP Java SDK version 1.0.0. Users should upgrade to version 1.0.0 or later to remediate this issue. No other official remediation level or temporary fix is provided. Patch status is confirmed by the vendor advisory stating the fix is included in version 1.0.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-03T20:09:02.826Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d5779eaaed68159a6ad786
Added to database: 04/07/2026, 21:31:10 UTC
Last enriched: 04/15/2026, 15:54:35 UTC
Last updated: 07/07/2026, 10:33:23 UTC
Views: 228
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